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Catalyst2950 and Catalyst2955 Switch Software Configuration Guide
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Chapter7 Clustering Switches Planning a Switch Cluster
Planning a Switch Cluster
Anticipating conflicts and compatibility issues is a high priority when you manage several switches
through a cluster. This section describes these guidelines, requirements, and caveats tha t yo u shou ld
understand before you create the cluster:
Automatic Discovery of Cluster Candidates and Members, page 7-5
HSRP and Standby Command Switches, page 7-11
IP Addresses, page 7-14
Host Names, page 7-15
Passwords, page 7-15
SNMP Community Strings, page 7-15
TACACS+ and RADIUS, page 7-16
Access Modes in CMS, page 7-16
Management VLAN, page 7-16
LRE Profiles, page 7-17
Availability of Switch-Specific Features in Switch Clusters, page 7-17
Refer to the release notes for the list of Catalyst switches eligible for switch clustering, including which
ones can be command switches and which ones can only be member switches, for t he required software
versions, and for the browser and Java plug-in configurations.
We do not recommend using the ip http access-class global configuration command to limit access to
specific hosts or networks. Access should be controlled through the cluster com mand switc h or by
applying ACLs on interfaces that are configured with an IP address.

Automatic Discovery of Cluster Candidates and Members

The command switch uses Cisco Discovery Protocol (CDP) to discover member switches, candidate
switches, neighboring switch clusters, and edge devices in star or ca sca ded topol o gies.
Note Do not disable CDP on the command switch, on cluster members, or on any cluster-capable switches that
you might want a command switch to discover. For more information about CDP, see Chapter 24,
“Configuring CDP.”
Following these connectivity guidelines ensures automatic discovery of the switch cluster, cluster
candidates, connected switch clusters, and neighboring e dge d evices:
Discovery through CDP Hops, page 7-6
Discovery through Non-CDP-Capable and Noncluster-Capable Devices, page 7-7
Discovery through the Same Management VLAN, page 7-8
Discovery through Different Management VLANs, page 7-9
Discovery of Newly Installed Switches, page 7-10